/*
 *    Copyright 2009-2012 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.apache.ibatis.mapping;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.Map;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.ibatis.executor.BaseExecutor;
import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;

/**
 * Vendor DatabaseId provider
 * 
 * It returns database product name as a databaseId If the user provides a
 * properties it uses it to translate database product name
 * key="Microsoft SQL Server", value="ms" will return "ms" It can return null,
 * if no database product name or a properties was specified and no translation
 * was found
 * 
 * @author Eduardo Macarron
 */
public class VendorDatabaseIdProvider
		implements DatabaseIdProvider {

	private static final Log log = LogFactory
			.getLog(BaseExecutor.class);

	private Properties properties;

	public String getDatabaseId(
			DataSource dataSource) {
		if (dataSource == null)
			throw new NullPointerException(
					"dataSource cannot be null");
		try {
			return getDatabaseName(dataSource);
		} catch (Exception e) {
			log.error(
					"Could not get a databaseId from dataSource",
					e);
		}
		return null;
	}

	public void setProperties(
			Properties p) {
		this.properties = p;
	}

	private String getDatabaseName(
			DataSource dataSource)
			throws SQLException {
		String productName = getDatabaseProductName(dataSource);
		if (this.properties != null) {
			for (Map.Entry<Object, Object> property : properties
					.entrySet()) {
				if (productName
						.contains((String) property
								.getKey())) {
					return (String) property
							.getValue();
				}
			}
			return null; // no match, return null
		}
		return productName;
	}

	private String getDatabaseProductName(
			DataSource dataSource)
			throws SQLException {
		Connection con = null;
		try {
			con = dataSource
					.getConnection();
			DatabaseMetaData metaData = con
					.getMetaData();
			return metaData
					.getDatabaseProductName();
		} finally {
			if (con != null) {
				try {
					con.close();
				} catch (SQLException e) {
					// ignored
				}
			}
		}
	}

}
